Electromagnetic Waves and the Doppler Effect

A distant galaxy is simultaneously rotating and receding from the earth. As the drawing shows, the galactic center is receding from the earth at a relative speed of uG = 1.8 x 10^6 m/s. Relative to the center, the tangential speed is vT = 0.3 x 10^6 m/s for locations A and B, which are equidistant from the center. When the frequencies of the light coming from regions A and B are measured on earth, they are not the same and each is different than the emitted frequency of 5.800 x 10^14 Hz.

Find the measured frequency for the light from each of the following.
a.) region A
b.) region B